Conventionally, prior art systems such as JP 2005-344587 A provide a pump called a uniaxial eccentric screw pump having structure in which a rotor formed into an external thread shape is inserted in an inside of a stator having an inner peripheral surface formed into an internal thread shape. Many stators adopted in the pump have structure in which a lining member made of rubber, a resin, or the like is inserted in an inside of a metal outer cylinder. In the stators adopted in a prior art systems, the outer cylinder and the lining member are fixed to each other through bonding or the like, which prevents positional shifts of the outer cylinder and the lining member and the positional shift of the lining member.